I've managed to make my copter takeoff in Tutorial 1 and now I would like to comand it using APM as in tutorial 2. However my copter never conects to the APM Planner. Each time I open it after running the mavlink_bridge.launch file nothing happens on the APM Planner.

to run my APM v2.0.23-r1. I tried establishing a connection manually on the top right of the APM2 window but it strangly closes afterwards. I also observe that when I open APM in the terminal, using this comand, he prints some warning messages saying it can't find some files, for example "Cannot open file ':/files/images/control/launch." . However, APM opens anyway, which makes me wonder if I should pay attention to these messages.

Could you help me understand my problem? If the problem is in APM, could you please suggest another version of the program so I can have better chances running it?